WO2014023053A1

WO2014023053A1 - Method for forming hollow box body provided with built-in component

Info

Publication number: WO2014023053A1
Application number: PCT/CN2012/081100
Authority: WO
Inventors: 王晔; 高德俊; 吴陆顺; 苏卫东; 孙岩; 姜林; 徐松俊; 刘亮
Original assignee: 亚普汽车部件股份有限公司
Priority date: 2012-08-08
Filing date: 2012-09-07
Publication date: 2014-02-13

Abstract

A method for forming a hollow box body provided with a built-in component comprises the following steps: a) feeding, wherein two sheets of plasticizing parisons are respectively laid off to two gaps formed by a preformed template and a mold semi-mold; b) closing the mold semi-mold and the preformed template; c) performing blow molding under high pressure; d) fracturing and fixing the sheet-shaped parison; e) preheating the parison connected to the built-in component; f) opening a mold, removing the preformed template; g) fixing the built-in component; h) performing secondary closing on the mold; i) cooling a blade position of the mold, and performing blow molding under high pressure to form the hollow box body.

Description

Hollow box forming method provided with built-in components

The present invention relates to a method of forming a blow molded hollow casing, and more particularly to a hollow casing blow molding method provided with a built-in assembly, which is particularly suitable for use in the manufacture of fuel tank blow molding. Background technique

Automotive plastic fuel tanks are widely recognized by customers for their light weight, safety performance, corrosion resistance, impact resistance, long service life and large design freedom. The HDPE 6-layer coextrusion blow molding technology with EV0H fuel barrier is the mainstream technology for plastic fuel tank manufacturing today. With the increasing awareness of environmental protection by the global government, relevant policies and regulations have imposed strict requirements on automobile OEMs. For example, California has introduced PZEV, which is a zero-emission, <20mg/24h regulation. For plastic fuel tanks produced by mainstream technology, the total evaporative emissions include gasoline in the fuel tank body, welding surfaces and fittings, leaks of seals, etc., generally in the hundreds of mg / 24h, so the PZEV emission standards for plastic fuel tanks Very demanding. At the same time, due to the emergence of new energy-saving technologies such as start-stop and PHEV, the noise caused by fuel sloshing inside the fuel tank is more obvious when the background noise is reduced. Therefore, it is necessary to carry a large wave-proof plate structure inside the fuel tank to reduce fuel consumption. The swaying noise, and the traditional wave-proof board can only enter the wave-proof board from the oil pump opening or the bottom of the parison into the tank, and the size of the wave-proof board is limited, so it requires a greater degree of process design freedom.

In order to achieve these goals, some fuel tank manufacturers have recently made breakthroughs in technology. For example, INERGY's TSBM technology uses the CORE structure to preform two blanks. The internal parts of the CORE are connected to the parison of the tank inner wall by the built-in mechanism inside the CORE; TI's TAPT process uses a special blow molding process to cut the pre-blow molded tank parison to obtain two parisons. The process then connects the internal parts to the inner wall of the tank to obtain a blown hollow body with built-in parts. TSBM technology uses the CORE structure to carry out the preform preforming and component built-in process in a long period of time, which is not conducive to the improvement of the design freedom of the tooling, is not conducive to the quality of the Haf line molding, and does not have good visibility of the debugging process; The TAPT technology needs to cut the formed fuel tank into two halves first, which is not conducive to improving the production efficiency of the fuel tank. At the same time, the function of the mold is complicated and the tooling cost is high. How to reduce the cost of equipment and products, improve product quality and tooling design freedom, and achieve good process visibility, minimize the leakage of hollow boxes, and can build large components such as wave boards, etc. A problem that needs to be solved. Summary of the invention

The invention is directed to the technical problems existing in the prior art, and provides a simple operation, lower cost, good quality, large degree of freedom in tooling design, and can realize a hollow box blowing with large built-in components compared with the prior art. Plastic molding method.

In order to solve the above technical problem, the technical solution of the present invention is as follows: A hollow box forming method provided with a built-in component, characterized in that the method comprises the following steps: a) feeding, the step is mainly two pieces The plasticized parisons are respectively fed into two gaps formed by the preforming template and the mold half mold;

b) the mold half mold and the preformed template are closed; C) high pressure blow molding;

d) breaking and fixing of the parison;

e) preheating the parison connecting the built-in components;

f) the mold is opened and the preformed template is withdrawn;

g) fixed built-in components;

h) the mold is closed twice;

i) The die edge is cooled and blow molded to form a hollow box.

As an improvement of the present invention, the temperature adjustment device for realizing the cold water hot water switching function is disposed at the knife edge position of the mold. After the mold half mold and the preform template are closed, the temperature adjustment device is switched before the high pressure blow molding. The parison is insulated by hot water, and the parison here needs to maintain a relatively high temperature, mainly to maintain the high temperature molten state of the parison and improve the final molding quality. After the mold is closed twice, the temperature adjustment device is switched to cold water to cool the mold edge, and the main function is to ensure the shape of the product and the mechanical properties at the edge.

As an improvement of the present invention, the pre-formed template is provided with a heating device. After the high-pressure blow molding is completed, the heating device heats the position of the parison that needs to be connected to the built-in component, and the heating temperature is controlled at 130-170 degrees Celsius. For the range of 150-160 degrees Celsius, the thermal device can be a contact heating device or a non-contact heating device, wherein the contact heating device is a hot plate heating component, and the non-contact heating device is an infrared heating component. Generally, after 5-10 seconds of high-pressure blow molding, the shape of the fuel tank has been basically formed. The heating device on the pre-formed template is driven by the cylinder, the cylinder or the motor, or is close to the position where the parison of the built-in component needs to be connected. The parison is heated, preferably at a temperature of 150-160 Celsius, the main role is to ensure the consistency of the parison temperature, improve the stability of product quality, the temperature is too high or too low will lead to inconsistency of the parison temperature, which in turn affects the quality of the whole product.

As an improvement of the present invention, after the high-pressure blow molding is completed, the blank is cut by a cutting member provided on the sheet forming device to realize the cutting and fixing of the parison. The main function of the cutting device is to realize the upper and lower division of the parison to meet the needs of continuous production of the fuel tank. In order to better realize the cutting function, the cutting member can be provided with a temperature control switch, and in addition, in order to prevent the cutting member from sticking to the parison, in cutting A coating is provided on the device to prevent bonding to the preform material HDPE, such as a Teflon coating or other fluorinated hydrocarbon; wherein the cutting member is a cutter or other splitter having a cutting action.

As an improvement of the present invention, the built-in component fixing step is that, in the step, the robot arm fixedly mounted on the main body moves the clamped component to be built into the position between the molds, and the robot The arm has a pushing device such as a cylinder, a cylinder or a motor for connecting the built-in parts with the parison inside the mold cavity. This connection can be one of welding, welding or riveting. Or the welding process generally requires a hot plate or infrared preheating before the connection to better achieve the connection performance.

As an improvement of the present invention, the preforming template is provided with a parison fixing device, in the breaking and fixing step of the parison blank, after the parison is broken, the parison is fixed to the mold by the parison fixing device. Upper part. After the material is broken, the main machine leaves the die cutting position, and the upper part of the pre-formed template device has a parison fixing device, and the movement of the baffle is pushed by the cylinder, the oil cylinder or the motor to push the upper part of the parison after the material is broken to Upper part of the mold and assist certain The pressure acts to fix the upper part of the parison on the upper surface of the mold to prevent the upper part of the parison from falling off in the subsequent step, which has an impact on the overall quality of the molding.

As an improvement of the present invention, the pre-formed template is provided with an air blowing device, the air blowing device is a diffusing air blowing head, and the air blowing head is configured as a porous hollow ball structure, and the structure can be realized to each Uniform blowing in the direction ensures that the position of the parison in all directions in the preforming process is evenly applied to the inner wall of the cavity. This structure is different from the conventional piercing needle blowing. The air blowing method pushes two parisons under the high pressure blowing to the surface of the mold cavity to realize the initial molding of the upper and lower casings of the oil tank, and the process is often completed within a few seconds, and the fuel tank casing of the process is basically formed. The shape of the fuel tank body is realized; the air blowing mode can obviously improve the production efficiency, can form a better shape of the Haf line, and further ensure the product quality.

As an improvement of the present invention, the pre-formed template is further provided with a sealing device for sealing between the mold, the parison and the pre-formed template, not only preventing the leakage of the high-pressure blow air from being insufficiently formed, but also preventing The exchange of heat with the outside causes a rapid decrease in the temperature of the parison, thereby realizing the parison preforming function in the step; the sealing device is a sealing strip. The sealing strip may be made of organic or inorganic materials having a certain strength, such as polytetrafluoroethylene or magnesium aluminum alloy. For the purpose of thermal conductivity and weight reduction, a better choice is a lightweight material of magnesium alloy. In the pre-forming, the flash parison outside the knife edge is squeezed to seal the mold, the preform template and the parison during the preforming, so that no leakage occurs under the action of the pre-blowing pressure, because once the air leak occurs It is easy to cause insufficient molding of the parison and cause heat exchange between the inside and the outside, which leads to excessive cooling and crystallization and hardening of the parison, which results in the quality of the inner part of the later part connected to the inside of the parison and the poor fusion quality at the edge, which affects the quality of the whole product. . Compared with the prior art, the present invention has the following advantages.

(1) With a diffuse blowing head, uniform blowing in all directions can be achieved, ensuring that the various positions of the parison are evenly attached to the inner wall of the cavity during the preforming process. The process is completed in a matter of seconds, not only improving production efficiency, but also forming a better Haf line to ensure the quality of the product.

(2) Contact and non-contact heating devices, contact heating can generally be understood as the heating plate heating method, non-contact heating can generally be understood as infrared heating mode. By heating the parison of the parison part that needs to realize the connection of the built-in parts in the later stage, it is prevented that the temperature of the parison is too low, resulting in poor connection quality. This heating function is also conducive to the stability of the surface temperature of the parison, and the connection position. Temperature control, reducing temperature fluctuations, is an effective solution to improve the quality of built-in components and hollow bodies;

(3) In the parison preforming stage, after the two parisons are broken, the parison is fixed on the upper surface of the mold by the parison fixing device, and the upper flash is prevented from being smashed after the preform is preformed, so that the mold is prevented from being second. When it is closed, the quality of the product is insufficient, and the quality of the sludge at the edge is formed.

(4) The preforming stencil device has a sealing strip on the outer side of the corresponding knife edge to seal the mold, the preform stencil and the parison during preforming, so that no air leakage occurs under the action of the pre-blowing pressure.

(5) The whole of the pre-formed stencil device has a heating function, and the pre-formed stencil device is heated by an external mold temperature machine, and the temperature is generally maintained at 80 degrees Celsius or more to prevent the parison at the knife edge position from being cooled too quickly during the pre-forming process. It is not conducive to the improvement of the quality of the knife edge when the final mold is closed. The invention provides a method for blow molding a two-piece plasticized parison hollow body, which realizes the connection between the built-in component and the inner wall of the oil tank, and reduces the opening of the fuel tank compared with the conventional perforated welding, such as a boring joint or a joint. Reduces the emission of HC compounds from the welding surface, reduces environmental pollution, meets the requirements of special area emission regulations, and increases the size of built-in parts, and increases the number of built-in parts such as wave-proof boards. Design freedom, better meet the performance of the tank against waves and noise. The invention also improves the molding quality and product yield of the product by using the pre-formed template device, so that the opening on the container wall is minimized, and an effective molding method is provided for realizing low leakage of the molded hollow box. DRAWINGS

Figure 1 is a schematic view of the feeding state;

Figure 2 is a schematic view showing the first closure of the mold half mold and the preformed template;

Figure 3 is a schematic view showing the exit state of the preformed template;

Figure 4 is a schematic diagram of the fixing of the built-in components;

Figure 5 is a schematic diagram of the secondary closure of the mold half mold and the preformed template;

Figure 6 is a schematic view showing the state in which the mold half mold is opened and ready to enter the next cycle;

Figure 7 is a schematic view showing the structure of the formed fuel tank.

In the figure: 1 is a parison, 2 is a mold half mold, 3 is a pre-formed template, 4 is a heating device, 5 is a robot arm, 6 is a parison fixing device, 7 is a blowing device, 8 is a sealing strip, 9 is The power unit, 10 is the base, 11 is the temperature adjustment device, 12 is the heating device, and 13 is the fuel tank. detailed description

In order to further understand the present invention, the present invention will be described in detail below with reference to the accompanying drawings. Example 1:

A hollow box forming method provided with built-in components, the method comprising the following steps:

Referring to Figure 1, a) feeding step, the preform template 3 and the mold half mold 2 are placed on the base 10 by the power unit 9, and when the two plasticized parisons start to be unloaded, the preform template and the mold half mold move. Below the parison 1, two plasticized parisons 1 are subsequently fed into the two gaps formed by the preformed stencil 3 and the mold halves 2, respectively. Referring to Fig. 2, b) the mold half mold 2 and the pre-formed template 3 are closed; the temperature adjustment device 11 for realizing the cold water hot water switching function is provided at the knife edge position of the mold, and after the mold half mold 2 and the preform template 3 are closed, the high pressure Prior to blow molding, the temperature regulating device heats the parison by switching to hot water, where the parison needs to maintain a relatively high temperature, mainly to improve the final molding quality. c) high pressure blow molding; the parison 1 sandwiched between the mold half mold 2 and the pre-formed template 3 is passed through the air blowing device 7 carried on the pre-formed template and/or the vacuum suction on the mold is attached to the mold half mold 2 blow molding preforms. d) Cutting and fixing of the parison; After the high-pressure blow molding is completed, the blank is cut by the cutting member provided on the sheet forming device to realize the cutting and fixing of the parison. The main function of the cutting device is to realize the upper and lower division of the parison to meet the needs of continuous production of the fuel tank. In order to better realize the cutting function, the cutting member can be provided with a temperature control switch, and in addition, in order to prevent the cutting member from sticking to the parison, in cutting On the device A coating is provided to prevent adhesion to the parison material HDPE, such as a Teflon coating or other fluorinated hydrocarbon; wherein the cutting member is a cutter or other cutting device having a cutting action. The preform template is provided with a parison fixing device 6, in which the parison of the parison is cut and fixed, and after the parison is broken, the parison is fixed to the upper portion of the mold by the parison fixing device 6. After the material is cut off, the main machine leaves the die unloading position, and the parison fixing device 6 of the upper part of the pre-formed template device pushes the baffle by the cylinder, the oil cylinder or the motor to push the upper part of the parison after the material is broken. In the upper part of the mold and assisting a certain pressure, the upper part of the parison is fixed on the upper surface of the mold to prevent the upper part of the parison from falling off in the subsequent step, which has an impact on the overall quality of the molding. e) Preheating of the parison connecting the built-in components; the pre-formed form is provided with a heating device 4, after the high-pressure blow molding is completed, the heating device heats the position of the parison to be connected to the built-in component, and the heating temperature is controlled at 130-170 degrees Celsius Preferably, the heating device is a contact heating device or a non-contact heating device, wherein the contact heating device is a hot plate heating component, and the non-contact heating device is an infrared heating component. Generally, after 5-10 seconds of high pressure blow molding, the shape of the fuel tank is basically formed, and the heating device 4 on the pre-formed template is contacted by the cylinder, the cylinder or the motor, or is close to the position where the parison of the built-in component needs to be connected, The parison is heated at a temperature of 150-160 degrees Celsius. The main function is to ensure the consistency of the parison temperature and improve the stability of the product quality. If the temperature is too high or too low, the temperature of the parison will be inconsistent, which will affect the influence. The quality of the entire product. Referring to Fig. 3, f) the mold half mold 2 is opened, and the pre-formed template 3 is ejected from the mold half mold by the power unit; during the mold opening and the pre-form template exit, the mold vacuum and the preforming template device are passed through the mold After the action, the parison is close to the mold cavity, and the preforming template device is smoothly realized. The mold half 2 and its parison 1 are separated and exit the position between the mold halves. Referring to Fig. 4, g) the built-in component is fixed; the built-in component fixing step is, in this step, the robot arm 5 fixedly mounted on the main body moves the clamped component to be built between the mold half mold 2 and needs to be built in The robot arm 5 is provided with a pushing device such as a cylinder, a cylinder or a motor for connecting the built-in parts with the parison inside the mold cavity, and the connection may be one of welding, welding or riveting. Generally, when a welding or welding process is used, it is generally required to perform hot plate or infrared preheating before, in order to better achieve the connection performance.

Referring to Figure 5, h) the mold is closed twice; after the mold is closed twice, the temperature adjustment device is immediately switched to cold water to cool the mold edge, and the main function is to ensure the shape of the product and the mechanical properties at the edge. i) The position of the die edge is cooled, and the blow molding forms a hollow box; in the second closing of the mold and the final blow molding step, the robot arm 5 realizes the connection of the built-in component to the inner wall of the fuel tank, and then returns to the initial position, ready to be clamped. Another set of built-in components goes into the next cycle. Close the mold half mold 2 and the preformed parison. At this time, the hot water inside the water channel at the mold edge is switched to cold water, and the cooling is performed at the knife edge when the mold is closed to ensure the shape of the product and the mechanical properties at the edge, and finally the assembly will be provided. The pre-formed blank blow-molded plastic hollow box body, see FIG. 7, the robot arm 5 holding device in the process is further provided with an image capturing device, which can shoot the welding surface of the parts connected to the inner wall and pass the image The identification monitors the connection position and shape to prevent the difference in product performance caused by poorly connected parts, and further ensures product quality. Example 2: The air blowing device is set to have a diffusing air blowing head, and the air blowing head is set to be more The hollow hollow ball structure can uniformly blow air in all directions to ensure uniform position of the parison in all directions to the inner wall of the cavity during the preforming process. After the mold, the preforming template device and the parison are closed, the air is blown through the air blowing head on the pre-formed template, and the air holes on the mold also need to open the vacuum suction blank to assist the molding function, and in the subsequent process. The utility model is used for adsorbing the parison to prevent falling off from the cavity. The structure is different from the traditional piercing needle blowing, which pushes the two parisons under the high pressure blowing to the surface of the mold cavity to realize the fuel tank. The initial molding of the upper and lower casings is often completed in a few seconds. The formation of the fuel tank casing of the process basically realizes the shape of the fuel tank body; the blowing method can significantly improve the production efficiency and can form a better haf The shape of the line, the further improvement of the product quality. Embodiment 3: The pre-formed template 2 is further provided with a sealing device for sealing between the mold, the parison and the pre-formed template, not only preventing the leakage of the high-pressure blown air from being insufficiently formed, but also preventing heat exchange with the outside world. The rapid decrease of the parison temperature is ensured, thereby ensuring the realization of the preform preforming in the step; the sealing device can be provided as a sealing strip 8, and the sealing strip can be made of organic or inorganic material having a certain strength, for example, poly four. Fluoroethylene or magnesium alloy, etc., for the thermal conductivity and weight reduction requirements, a better choice is the lightweight material of magnesium alloy. In the pre-forming, the flash parison outside the knife edge is squeezed to seal the mold, the preform template and the parison during the preforming, so that no leakage occurs under the action of the pre-blowing pressure, because once the air leak occurs It is easy to cause insufficient molding of the parison and cause heat exchange between the inside and the outside, which leads to excessive cooling and crystallization and hardening of the parison, resulting in the quality of the inner part of the later part connected to the inside of the parison and the poor fusion quality at the edge, thus affecting the whole product. Embodiment 4: In order to improve the efficiency of the production process, in the preform pre-blowing molding process, the built-in components may be heated by the heating device 12, and the preheating operation may be performed at any time when the built-in components are fixed.

It should be noted that the above-described embodiments are merely preferred embodiments of the present invention, and are not intended to limit the scope of the present invention. The equivalent transformations made on the basis of the above methods are all within the scope of the present invention.

Claims

Rights request

1. A hollow box forming method provided with built-in components, characterized in that the method includes the following steps:

a) Feeding, this step mainly involves feeding two pieces of plasticized parisons into the two gaps formed by the preform template and the mold half;

b) The mold half and the preformed template are closed;

c) High pressure blow molding;

d) Cutting and fixing of sheet blanks;

e) Preheating of parison connecting built-in components;

f) The mold is opened and the preformed template exits;

g) Fixed built-in components;

h) Secondary closing of the mold;

i) The mold knife edge is cooled and blow molded under high pressure to form a hollow box.

2. The hollow box molding method provided with built-in components according to claim 1, characterized in that a temperature adjustment device for switching between cold and hot water is provided at the knife edge of the mold. After the molding template is closed and before high-pressure blow molding, the temperature regulating device switches to hot water to keep the parison warm; after the mold is closed for the second time, the temperature regulating device switches to cold water to cool the mold knife edge.

3. The hollow box molding method provided with built-in components according to claim 1, characterized in that the preformed template is provided with a heating device, and after the high-pressure blow molding is completed, the heating device needs to be connected to the built-in components The parison is heated, and the heating temperature is controlled at 130-170 degrees Celsius.

4. The hollow box molding method provided with built-in components according to claim 1, characterized in that after the high-pressure blow molding is completed, the blank is cut by a cutting component provided on the sheet forming device to achieve sheeting. Cutting and fixing of body blanks.

5. The hollow box forming method provided with built-in components according to any one of claims 1 to 4, characterized in that the step of fixing the built-in components is to connect the built-in components to the required position through a robot arm. position, the connection method adopts one of welding, welding or riveting.

6. The hollow box molding method provided with built-in components according to any one of claims 1 to 4, characterized in that, the preform template is provided with a parison fixing device, and the sheet body blank is cut off In the fixing step, after the parison is broken, the parison is fixed on the upper part of the mold through the parison fixing device.

7. The hollow box molding method provided with built-in components according to any one of claims 1 to 4, characterized in that the preformed template is provided with an air blowing device, and the air blowing device is a belt The divergent air blowing head is configured as a porous hollow ball structure.

8. The hollow box forming method provided with built-in components according to any one of claims 1 to 4, characterized in that the preformed template is also provided with a sealing device.

9. The hollow box forming method provided with built-in components according to claim 7, characterized in that the sealing device is a sealing strip.

10. The method of forming a hollow box with built-in components according to claim 3, wherein the heating device is a contact heating device or a non-contact heating device, and the contact heating device is a hot plate heating component. , the non-contact heating device is an infrared heating component.

11. The hollow box molding method provided with built-in components according to claim 4, characterized in that the cutting component is a knife or a divider with a cutting function, and the cutting component is provided with a parison to prevent adhesion of the parison. coating.